Wee'ing in the wrong place

My 2.5 year old has been out if nappies for about 3 months. We have a few accidents but are getting there.. Or so I thought. For the last 4 or 5 days, DD has taken to doing a wee outside on the decking. I have no idea why (no traumas or changes going on) and I don't know how to handle it. A trip to the ice cream shop was promised if she did all her wees in the right place yesterday but even that didn't work (cue floods of tears). She knows she's doing something she shouldn't do and that she will be sent to her room but she still persists. Oh, its not because shes been caught short - ive seen her go outside just to do it. Help!

It sounds a bit harsh to send her to her room. Punishment actually makes behavior worse so if she's been punished for stuff this could actually be why she's wee ing on the decking. Maybe try some more positive didcipline techniques and she might feel more like co operating with you and wee ing in the right place